I did literally no revision for my GCSE's last year despite being expected all A-A*s. As long as you can get into your college courses (normally just 5 C's min) or whatever you want to do next you should be good, don't fret lads.
Great video. Check this one out as well, very inspirational. You don't need a degree to get somewhere in life. You need ideas, passion, dedication. If you don't build your own dream, someone else will hire you to help built theirs.
Schools only prepare you for a test on a given date. But life is so much more. Life is a constant test and results you achieve today have no meaning tomorrow. Tests do not prepare you for life, life is the test itself.